Safe Transposition

2nd-level conjuration
Casting time: 1 reaction, which you take when an injured ally is attacked
Range: 30 feet
Target:
Components: S
Duration: Instantaneous
Classes: Paladin,
Subclasses:

You cast this spell when an ally below half its hit point maximum within range is attacked. You swap places with your ally, each of you instantly teleporting into the space the other just occupied. If there isn’t room for you in the new space or for your ally in your former space, this spell fails. After the two of you teleport, the triggering attack roll is compared to your AC to determine if it hits you.